• Imaging Science in Dentistry
• /
• v.32 no.2
• /
• pp.81-87
• /
• 2002

Purpose : To investigate the diagnostic significance of cortical changes in the bone of diseased jaws utilizing computed tomography (CT). Materials and Methods: Computed tomographic images of 91 patients, consisting of 7 osteomyelitis, 46 cysts, 18 benign tumors, and 20 malignant tumors, were analyzed. The pattern of cortical expansion was classified into three types: no expansion (N), buccal or lingual expansion (B/L), and buccolingual expansion (B & L). The pattern of cortical destruction was classified into four types: no destruction (N), point destruction (PO), gross destruction (GR), and permeative destruction (PE). The pattern of periosteal reaction was classified into four types: parallel, irregular, spicule, and Codmans triangle. The relationship between the pattern of cortical bone changes and diseases of the jaws was assessed. Results: When the pattern of cortical expansion was compared to diseases of the jaw, N-type was most prevalent in cases of osteomyelitis and malignant tumors, B/L-type with cysts, and B&L-types with benign tumors. Comparison between the pattern of cortical bone destruction with diseases of the jaw showed strong correlations between PO and PE-types to osteomyelitis, N-type with cysts, N and GR-types with benign tumors, and GR-type with malignant tumors. Finally, the relationship between the pattern of periosteal reaction to diseases of the jaw showed a strong correlation between parallel-type to osteomyelitis and spicule-type to malignant tumors. Conclusion : The pattern of cortical expansion and cortical destruction is useful in differentiating diseases of the jaws.

• The korean journal of orthodontics
• /
• v.37 no.1 s.120
• /
• pp.5-15
• /
• 2007

Objective: The purpose of this study was to evaluate the mechanical performance of mini-screws during insertion into artificial bone with use of the driving torque tester (Biomaterials Korea, Seoul, Korea), as well as testing of Pull-out Strength (POS). Methods: Experimental bone blocks with different cortical bone thickness were used as specimens. Three modules of commercially available drill-free type mini-screws (Type A; pure cylindrical type, Biomaterials Korea, Seoul, Korea, Type B; partially cylindrical type, Jeil Medical, Seoul, Korea, Type C; combination type of cylindrical and tapered portions, Ortholution, Seoul, Korea), were used. Results: Difference in the cortical bone thickness had little effect on the maximum insertion torque (MIT) in Type A mini-screws. But in Type B and C, MIT increased as the cortical bone thickness Increased. MIT of Type C was highest in all situations, then Type B and Type A in order. Type C showed lower POS than Type A or B in all situations. There were statistically significant correlations between cortical bone thickness and MIT, and POS for each type of the mini-screws. Conclusion: Since different screw designs showed different insertion torques with increases in cortical bone thickness, the best suitable screw design should be selected according to the different cortical thicknesses at the implant sites.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.49 no.2
• /
• pp.100-104
• /
• 2023

Autogenous bone grafts from the mandibular ramus are a known source of inadequate bone volume scenarios of the residual alveolar ridge. However, the conventional block-type harvesting technique cannot prevent bone marrow invasion, which can cause postoperative complications such as pain, swelling, and inferior alveolar nerve injury. This study aims to suggest a complication-free harvesting technique and present the results of bone grafting and donor sites. One patient received two dental implants with a complication-free harvesting technique that involves creation of ditching holes with a 1 mm round bur. Sagittal, coronal, and axial osteotomies produced grid-type cortical squares using a micro-saw and a round bur to confirm the cortical thickness. The grid-type cortical bone was harvested from the occlusal aspect, and the harvesting was extended through an additional osteotomy on the exposed and remaining cortical bone to prevent bone marrow invasion. The patient did not suffer postoperative severe pain, swelling, or numbness. After 15 months, the harvested site exhibited new cortical bone lining, and the grafted area had healed to a cortico-cancellous complex with functional loading of the implants. Our technique, grid-type cortical bone harvesting without bone marrow invasion, allowed application of autogenous bone without bone marrow invasion to achieve acceptable bone healing of the dental implants and to regenerate the harvested cortical bone.

• The Journal of Korean Physical Therapy
• /
• v.21 no.1
• /
• pp.73-80
• /
• 2009

Purpose: In order to examine difference in the activity of potential of spinal neurons and cortical neurons according to muscle contraction type in post stroke hemiplegic subjects and healthy subjects, the present study conducted an experiment as follows. Methods: The subjects in the experimental group were 17 left-side hemiplegic subjects (9 female, 8 male; mean age, 63.41$\pm$9.86 years) with the right hand as the dominant hand selected among post stroke hemiplegic subjects, and 17 age matched healthy control subjects (10 female, 7 male; mean age, 64.12$\pm$12.07 years). Movement-related cortical potentials (MRCPs) were measured using surface electromyography and electroencephalography while concentric and eccentric movements were made alternately. Results: As to the pattern of the activity of MRCP, which indicates the activity of motor cortical neurons, we found that the amplitude is high (p<0.01), the length of excitement is short (p<0.01) and the ascending gradient of amplitude to the peak increases (p<0.05) in post stroke hemiplegic subjects' lesion sites different from healthy subjects. Conclusion: The activity of cortical neurons was no difference in activity according to contraction type was observed in post stroke hemiplegic subjects' lesion sites. This suggests that there is no distinction in the activity of cortical neurons between concentric contraction and eccentric contraction. Accordingly, if post stroke hemiplegic subjects' activity of motor cortex is analyzed by measuring MRCPs, it is considered useful in research on neural plasticity or as a ground of clinical effects in the area of physical therapy for the central nervous system.

• Journal of Chest Surgery
• /
• v.27 no.9
• /
• pp.785-792
• /
• 1994

In this study, the authors analyzed the prognostic value of four clinical variables[age and sex of patients, association with myasthenia gravis and clinical stage] and histological type in 30 consecutive patients with thymoma, histologically classified as cortical[10],medullary[5] and mixed[15]type according to Marino and Muller-Hermelink classification. There were significant differences between the histological types in the frequency of the different tumor stages and myasthenia gravis and prognosis.Most of the cortical thymomas were at stage III and all of the medullary and most of the mixed tumors at stage I or II.Myasthenia gravis occurred more commonly in patients with cortical[30%] and mixed thymoma[60%] than in patients with medullary thymoma[10%]. Follow-up was conducted in 30 patients,with follow-up range from 3 months to 120 months[mean,47.3months]. 5 year actuarial survival was 100% for medullary thymoma, 73% for mixed thymoma, and 47% for cortical thymoma.The overall survival curve shows that 87.6% of the patients are alive at 2 years and 72.8% at 5 years. And 7 patients was dead during follow-up periods.By Kaplan-Meier technique, we found that the patients who had myasthenia gravis had better prognosis[P<0.05]. Medullary thymoma is a comparatively rare, benign tumor, and usually not associated with myasthenia gravis. Cortical thymoma must be regarded as malignant. Mixed thymoma is intermediate in its behavior between medullary and cortical thymoma. But these tumors should be considered potentially malignant despite of presence as stage I of II disease. Also, the patients with stageI,II had good prognosis and the patients with total resection had good prognosis[P<0.05].

• Proceedings of the Ginseng society Conference
• /
• 2007.12a
• /
• pp.62-62
• /
• 2007

• The korean journal of orthodontics
• /
• v.44 no.1
• /
• pp.36-43
• /
• 2014

Objective: The purpose of this study was to quantitatively evaluate the cortical bone densities of the maxillary and mandibular alveolar processes in adults with different vertical facial types using cone-beam computed tomography (CBCT) images. Methods: CBCT images (n = 142) of adult patients (20-45 years) were classified into hypodivergent, normodivergent, and hyperdivergent groups on the basis of linear and angular S-N/Go-Me measurements. The cortical bone densities (in Hounsfield units) at maxillary and mandibular interdental sites from the distal aspect of the canine to the mesial aspect of the second molar were measured on the images. Results: On the maxillary buccal side, female subjects in the hyperdivergent group showed significantly decreased bone density, while in the posterior region, male subjects in the hyperdivergent group displayed significantly decreased bone density when compared with corresponding subjects in the other groups (p<0.001). Furthermore, the subjects in the hyperdivergent group had significantly lower bone densities on the mandibular buccal side than hypodivergent subjects. The maxillary palatal bone density did not differ significantly among groups, but female subjects showed significantly denser palatal cortical bone. No significant difference in bone density was found between the palatal and buccal sides in the maxillary premolar region. Overall, the palatal cortical bone was denser anteriorly and buccal cortical bone was denser posteriorly. Conclusion: Adults with the hyperdivergent facial type tend to have less-dense buccal cortical bone in the maxillary and mandibular alveolar processes. Clinicians should be aware of the variability of cortical bone densities at mini-implant placement sites.

• The Journal of the Korean bone and joint tumor society
• /
• v.5 no.1
• /
• pp.17-22
• /
• 1999

Over 60 cases were enlisted, but only 31 cases among 24 patients were eligible with a minimum follow-up of 1 year and complete medical documents with imaging data. There were 18 boys and 6 girls, and 7 patients had bilateral lesions. The age of the patients ranged from 2 to 20 years(mean:10.5 years). At their first visit, most lesions had a highly characteristic location and radiographic appearance of radiolucent lesion(s) ranging from 1 to 3cm, except for one case of 5.5 cm in the posteromedial comer of distal femoral metaphysis. The margins were generally well-defined, although some were ill-defined. After reviewing our cases from the viewpoint of clinical course and radiographic patterns, we divided these lesions into two types. Type I is the osteolytic lesion excavated into the posteromedial aspect of the distal femur without cortical defect; and type II is the buldged out lesion of the femur with cortical irregularity into the surrounding soft tissues. Both types have distinctive clinical courses. Type I lesions were easy to make a definite diagnosis with plain radiographs alone, but in type II, it was sometimes very difficult to differentiate it from malignant tumors or chronic localized osteomyelitis. For this lesion, Gd-enhanced MRI was the most effective method for differential diagnosis. In this study, biopsy was not necessary to confirm the diagnosis. Clinical symptoms of type I were very minor or even absent. Many of them were accidentally found after minor trauma around the knee joint. Clinical symptoms disappeared far earlier than radiographical lesions. No treatment such as restriction of activity or drugs was necessary. For type II, the clinical symptoms were more accentuated and lasted longer, and it was necessary to restrict the activity for a certain period in many cases. However, all were self-limited.

• Journal of Korean Neurosurgical Society
• /
• v.62 no.3
• /
• pp.288-295
• /
• 2019

In 2011, the International League against Epilepsy (ILAE) proposed a first international consensus of the classification of focal cortical dysplasia (FCD). This FCD classification had been widely used in worldwide. In this review paper, the authors would like to give helpful comments for better understanding of the current FCD classification. Especially, the basic concepts of FCD type I, such as "radial", "tangential" and "microcolumn" will be discussed with figures. In addition, the limitations, genetic progress and prospect of FCD will be suggested.

• Investigative Magnetic Resonance Imaging
• /
• v.7 no.1
• /
• pp.47-55
• /
• 2003

Purpose : Cortical dysplasia is known to be of variety of MR imaging findings. We attempted to classify MR imaging findings of cortical dysplasia into several types and to correlate those with histopathologic grades and subtypes. Materials and Methods : Preoperative MR images of 97 patients with pathologically-proven cortical dysplasia were retrospectively reviewed with knowledge of the diagnosis and operative sites. The patients were divided into MR-positive and MR-negative groups based on the presence or absence of MR imaging abnormalities. In MR-positive group, MR imaging features were arbitrarily classified into four types (atrophic, cortical-band, inward-rounding, and nonspecific types) on the basis of size of the gyrus and adjacent CSF space, cortical thickness, signal intensity of the subcortical white matter, and blurring of the gray-white matter junction. The pathologic findings were also retrospectively reviewed without knowledge of MR imaging findings and divided into three grades (mild, moderate, and severe) and two subtypes (nonballoon-cell and balloon-cell). Pathologic grades and subtypes we re compared between MR-positive and MR-negative groups. Four MR types of the MR-positive group were correlated with the pathologic grades and subtypes. Results : MR-positive and MR-negative groups consisted of 39 (40%) and 58 (60%) patients, respectively. Of the MR-positive group, atrophic type was seen in 13 patients (33 %), cortical-band type in 9 (23%), inward-rounding type in 9 (23%), and nonspecific type in 8 (21%). There was no significant difference in the pathologic grades between MR-positive and MR-negative groups, although MR-positive group tended to have higher pathologic grades than MR-negative group did. Balloon-cell subtype was found significantly higher in MR-positive group than in MR-negative group (p<0 .05): 21% (8/39) versus 5% (3/58). The inward-rounding type corresponded to the pathologically severe grade and balloon-cell subtype in 78% (7/9) and 56% (5/9) of the patients, respectively, while the atrophic type to the mild grade and nonballoon-cell subtype in 77% (10/13) and 100% (13/13), respectively. Conclusion : A variety of MR imaging abnormalities were found in 40% of the patients with cortical dysplasia and those were classified into four types (atrophic, cortical-band, inward-rounding, and nonspecific types), of which the inward-rounding type correlated well with the pathologically severe grade and balloon-cell subtype, whereas the atrophic type with the mild grade and nonballoon-cell subtype.